. >> president obama toured fema headquarters and says the federal government is standing by to provide any assistance it can. >> reporter: i hope you can get a sense here of just how huge these waves have become. they have broached the board walk. the water is under the hotels and restaurants. it's quite an indication of how much this water is going to be piling up later. >> no kidding. and we know a lot of power outages are expected. anything in that area so far? >> reporter: no. all the power is still on for now. but there is a lot of anticipation, there are going to be rolling blackouts. and utility crews are out here trimming trees trying to keep the power lines clear. when this water really starts moving inland, if there's wind, could topple the trees and bringing down the power lines. >> okay. stay safe out there. susan live in delaware. thank you. >> hurricane sandy is affecting air travel worldwide even at sfo. all flights have been canceled for the next 48 hours. elissa over at sfo speaking with some of the travellers. have most of them gotten the warning or are some surprised